Applications may require circuits that can boost up an input power supply direct current (DC) voltage to a higher DC voltage. One reason for the voltage boost up is that often only standardized power supply voltages are available for supplying power to electronic circuits. However, a circuit may need a higher voltage than is available from the associated power supply. One example of such a circuit is a “flash memory” such as an electrical erasable programmable read only memory (EEPROM).
A flash memory may include an array of memory cells each typically storing a plurality of bits of digital information. A memory cell may include a field effect transistor (FET) that includes a gate that holds a charge that corresponds to a bit of digital information (termed herein as a “bit charge”). More specifically, a memory cell FET may include a drain, a gate, and a source. The gate may include a control gate for enabling reading, writing, and erasing operations on the cell, and a floating gate for storing the bit charge of digital information. In addition to these gates, some memory cells may include an erase gate for removing the bit charge from the floating gate, thereby erasing the memory cell.
In a flash memory circuit, a majority of the circuit operations may require a voltage on the order of 1.5 volts, for example. Thus, the design of the power supply for the flash memory circuit may include a 1.5 volt power supply. However, to generate a higher voltage for writing and erasing operations, a DC voltage boost circuit may be used that takes the normal power supply voltage of 1.5 volts and boosts it up to about six (6) volts, for example, to perform these higher voltage operations. Other voltage values may also be provided.